[PATCH] D107880: [AArch64][SVE] Remove assertion/range check for i16 values during immediate selection

[Usman Nadeem via Phabricator via llvm-commits]

mnadeem created this revision.
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This assertion fails when an i16 constant is promoted to i32.
Example: https://godbolt.org/z/rxo649jEo

The value `i16 -32768` is within the range of i16 but is promoted to
positive `i32 32768` by an earlier call to `DAG.getConstant()`.

Another option would be to modify the assert to:

  assert((ImmVal >= -32768) && (ImmVal <= 65535));

not sure if this is any better.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D107880

Files:
  llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp


Index: llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
@@ -3152,7 +3152,6 @@
         Imm = CurDAG->getTargetConstant(ImmVal, DL, MVT::i32);
         return true;
       } else if ((ImmVal & 0xFF) == 0) {
-        assert((ImmVal >= -32768) && (ImmVal <= 32512));
         Shift = CurDAG->getTargetConstant(8, DL, MVT::i32);
         Imm = CurDAG->getTargetConstant((ImmVal >> 8) & 0xFF, DL, MVT::i32);
         return true;


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